The machine referred to above is of the type disclosed, for example, in U.S. Pat. No. 5,826,492 and US-A-2003/217644, and comprises pressurized-hot-water dispensing means, in turn comprising a boiler, and a sprinkler having an end wall; a removable percolating cup for housing a sealed capsule of the type described above, and positioned, in use, with its inlet facing the end wall; supporting and retaining means for retaining the percolating cup, in use, in a work position connected to the end wall; a first piercing device carried by the sprinkler to permit pressurized-hot-water flow through the sealing wall; and a second piercing device carried by the percolating cup to permit outflow of the beverage through the bottom wall; the first piercing device comprising a number of projections extending towards the supporting and retaining means from a peripheral portion of the end wall; and the dispensing means, the supporting and retaining means and the percolating cup being aligned, in use, along an axis.
Though the machine according to the present invention is suitable for percolating any type of beverage by feeding pressurized hot water through anhydrous powdered material in a sealed capsule, specific reference is made in the following description, purely by way of example, to a machine for producing a coffee beverage using a sealed capsule containing a respective measure of ground coffee.
Known percolating machines employing sealed capsules of the type described above are normally enclosed machines, in which the piercing devices are only accessible from the outside by removing at least part of the machine, and may be, as is normally the case, needle devices.
In the case, however, of percolating machines of the above type, in which the percolating cup is removable, so that at least the first piercing device is accessible from the outside, using a needle-type first piercing device would be relatively dangerous, particularly when servicing or cleaning the machine.